The leukotrienes constitute a group of locally acting hormones, produced in living systems from arachidonic acid. The major leukotrienes are Leukotriene B.sub.4 (LTB.sub.4), LTC.sub.4, LTD.sub.4 and LTE.sub.4. The biosynthesis of these leukotrienes begins with the action of the enzyme 5-lipoxygenase on arachidonic acid to produce the epoxide known as Leukotriene A.sub.4 (LTA.sub.4), which is converted to the other leukotrienes by subsequent enzymatic steps. Further details of the biosynthesis as well as the metabolism of the leukotrienes are to be found in Leukotrienes and Lipoxygenases, ed. J. Rokach, Elsevier, Amsterdam (1989). The actions of the leukotrienes in living systems and their contribution to various diseases states are also discussed in the book by Rokach.
The art describes certain quinoline-containing compounds as having activity as antagonists of the actions of the leukotrienes. Thus, EP 318,093 (Merck) describes compounds of structure A. Structure B is disclosed in EP 315,399 (Rorer). Structures C and D are described in EP 348,155 (Rorer) and WO 89/04303 (Rorer). ##STR2##